Lawmakers in Iran have once again raised the possibility of leaving the Nuclear Non-Proliferation Treaty (NPT) as tensions over Tehran's nuclear program and its standoff with the United States continue.

Iranian MP Ghasem Ravanbakhsh said a proposal to withdraw from the landmark treaty had been submitted and was being considered.

Ebrahim Rezaei, a member of the National Security and Foreign Policy Commission, said a withdrawal would be the "best response" to increased US economic pressure.

The idea is not new. Iranian officials and lawmakers have repeatedly raised it during periods of tension with Western governments. However, it remains unclear whether Tehran is actually preparing to leave the treaty or whether the threat itself is the objective.

What would leaving the nuclear treaty mean?